This invention relates to triiodized carboxylic acid anilides and to processes for their preparation and use.
Compounds suitable for use as radiodiagnostic agents, especially for intravenous uro-, angio- and cholegraphy, must meet very high requirements with respect to vascular system compatibility and pharmacological inertness.
The use of radioactively labeled compounds as auxilliary agents for the observation and explanation of biochemical processes has been known for a long time: For example, for the development of medicines and for diagnostic purposes; i.e., for the liver function test, tetrachlorotetraiodofluorescein-I.sup.131, bromthalein-I.sup.131, and gold colloid Au.sup.198 have been employed. However, these compounds all exhibit various disadvantages.
In the case of tetrachlorotetraiodofluorescein-I.sup.131, it is difficult to produce a uniform unlabeled substance; moreover, during the labeling, radioactive by-products are formed having varying activity contents.
In the case of bromthalein-I.sup.131, as with tetrachlorotetraiodofluorescein-I.sup.131, the maximum accumulation in the liver and the elimination from the liver take place after a longer period of time, requiring longer examination times and a higher exposure to radiation.
Gold colloid Au.sup.198 is only suitable for representing the liver by scintigraphy and does not provide a direct functional diagnosis.
In contrast thereto, it has now been found that dicarboxylic acid anilides, containing radioactive iodine, of this invention, as well as the salts thereof with physiologically compatible bases, do not exhibit these disadvantages. After being labeled with a radioactive iodine isotope, they represent excellent agents for the functional conductance of diagnostics on the hepatic cells themselves.